This video introduces "Diso 6," a new six-output, galvanically isolated distribution amplifier designed for RF signals. The device features a compact aluminum enclosure, flexible USB-C (with Power Delivery negotiation for 15V/12V) and DC barrel jack power inputs, and robust BNC connectors with ample spacing. Internally, the design utilizes an AD8099 operational amplifier and transformers to provide isolation and amplification. The demonstration, using a spectrum analyzer and a signal generator, confirms a linear response up to approximately 200 MHz, with very clean sine wave outputs and harmonics typically 40-45 dB below the carrier. The unit achieves output amplitudes of around 30 dBm at 10 MHz and 11 dBm at 100 MHz, highlighting its effectiveness in distributing stable and isolated RF signals across multiple channels.
Diso 6: A Galvanically Isolated RF Distribution Amplifier
0:00 Introduction to Diso 6: The video introduces a new project, the Diso 6, a distribution board designed to provide isolated signal outputs, evolving from a previous GPSDO project.
0:43 Six Galvanically Isolated Outputs: The Diso 6 unit features one input and six galvanically isolated 50-ohm outputs, preventing interference and ground loops between connected instruments. Four outputs are on the front, and two on the back to maintain a compact size.
1:02 Spacious BNC Connectors: The BNC connectors are spaced approximately 33-34 mm apart to accommodate even thick BNC cables, ensuring practical usability.
1:43 Flexible Power Input: The device supports USB-C with Power Delivery (negotiating 15V then 12V) and a standard DC barrel jack (12-24V). A minimum of 12V is required, and maximum power consumption is around 300 mAh with all outputs terminated.
2:56 Input Specifications & Build Quality: The input connector can handle a maximum of 17 dBm (with protection circuitry) for 190 MHz. The unit boasts a solid aluminum enclosure, injection-molded plastic parts, and high-quality labeling.
3:38 Internal Design: The PCB is a revision of an open-source project, utilizing an AD8099 operational amplifier and transformers for isolation. It can achieve output amplitudes of 30 dBm at 10 MHz and around 11 dBm at 100 MHz.
4:30 Performance Testing Overview: The device's performance is tested using a spectrum analyzer to demonstrate its linearity, output levels, and spectral purity across various frequencies.
5:45 Linear Frequency Response: A tracking generator test shows a linear response from 100 kHz up to about 200 MHz, with significant roll-off beyond 250 MHz, making it reliably usable up to 200 MHz.
7:06 Amplification and Clean Signal: With a 0 dBm input, the device provides a 4 dBm output, indicating a slight amplification. Using a signal generator, a 10 MHz input produces an "absolutely clean sine wave" output with harmonics around 45 dB down.
9:47 Consistent Performance Across Frequencies: The distribution amplifier maintains very clean, sharp output tones at various frequencies, including 1 MHz (12 dBm output), 500 kHz (14 dBm output), 20 MHz (harmonics 43-45 dB down), 50 MHz (10 dBm output), 100 MHz (11 dBm output), and 120 MHz (10.44 dBm output).
13:30 Key Takeaway: The Diso 6 successfully verifies its performance as a reliable, galvanically isolated RF distribution amplifier, a unique design well-suited for various applications.